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The following cyber advisory was issued by the New York State Office of Information Technology Services and is intended for State government entities. The information may or may not be applicable to the general public and, accordingly, the State does not warrant its use for any specific purposes.

ITS ADVISORY NUMBER:
2013-099

DATE(S) ISSUED:
10/8/2013

SUBJECT:
Multiple Vulnerabilities in Microsoft Excel Could Allow Remote Code Execution (MS013-085)

OVERVIEW:

Multiple vulnerabilities have been discovered in Microsoft Office Excel, a spreadsheet application. These vulnerabilities could allow remote code execution if a user opens a specially crafted Excel file with an affected version of Microsoft Excel.  Successful exploitation could result in the attacker gaining the same user rights as the current user.  Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

SYSTEMS AFFECTED:

  • Microsoft Office 2007
  • Microsoft Office 2010
  • Microsoft Office 2013
  • Microsoft Office 2013 RT
  • Microsoft Office for Mac
  • Microsoft Excel Viewer
  • Microsoft Office Compatibility Pack

RISK:
Government:

  • Large and medium government entities: High
  • Small government entities: High

Businesses:

  • Large and medium business entities: High
  • Small business entities: High

Home users: High

DESCRIPTION:
Two vulnerabilities have been discovered in Microsoft Office Excel that could allow remote code execution.  These vulnerabilities exist due to the way that Microsoft Excel parses content in Excel files. An attacker who successfully exploited this vulnerability could take complete control of an affected system. Successful exploitation of this vulnerability could result in an attacker gaining the same privileges as the logged on user.  Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

RECOMMENDATIONS:
We recommend the following actions be taken:

  • Apply appropriate patches provided by Microsoft to vulnerable systems immediately after appropriate testing.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • Remind users not to open email attachments from unknown users or suspicious emails from trusted sources.
  • Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources.

REFERENCES:
Microsoft:
http://technet.microsoft.com/en-us/security/bulletin/ms13-085

CVE:
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3889
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-3890